Thank you all again! This information is excellent. I am looking at the maps again, and have added a few more towns that seem to have gas and hotels -- in case we want to push a day's drive on I-40 a little further. We have never done this, so I don't know what to expect.
Will we want to get off the highway and explore random cities and towns?, or will seeing what we see from I-40 and the rest- and restaurant/walking around stops we'll be making, be enough?
Any reasons that we would, or should, not want to stop in any of these towns:
Belle Meade, TN
Morrilton, AR
Clinton, OK
Tucumcari, NM
Barstow, CA (not on I-40 but close to a major road)
They all seem to have decent gas/food/lodging options close to I-40 or other major road. Please keep the advice and suggestions coming! ;-)